{
  "selected_configuration": "single-pass reflux receiving region with opposite outgoing downcomer",
  "fixed_internal_endpoint": "marked receiving point above selected tray",
  "external_candidates": [
    {
      "id": "A",
      "route": "near endpoint, short internal turn down to delivery"
    },
    {
      "id": "B",
      "route": "another external entry, internal extension and bends to same endpoint",
      "added_interfaces": [
        "internal length/fittings",
        "supports",
        "assembly/removal",
        "tray and manway interference"
      ]
    }
  ],
  "overlay_rule": "alternative routes, not simultaneous connected piping; crossings imply no joint",
  "separate_duties": [
    {
      "duty": "two-pass liquid feed",
      "alternatives": [
        "two external nozzles to two selected receiving regions",
        "single nozzle to distributing assembly serving both regions"
      ],
      "verification": "own coherent tray/downcomer/support/removal design"
    },
    {
      "duty": "reboiler or side draw-off",
      "endpoint": "selected liquid collection/sump region with actual seal and takeoff relationship",
      "not_equivalent_to": "feed or reflux discharge over tray"
    }
  ],
  "optional_internal_flange": "selected removable tray or internal pipe/tray-manway interference basis only",
  "conditions": [
    "distribution and inlet velocity",
    "liquid/foam obstruction",
    "internals support",
    "actual elevation/clearance",
    "vessel and internals review"
  ],
  "generic_angle_or_clearance": null
}